The invention relates to a fluid power linear drive comprising a drive housing having a housing tube and terminating walls arranged terminally thereon, at least one terminating wall being in the form of a housing cover separate from the housing tube having a centering portion fitting into the housing tube, said centering portion having on its outer periphery an annular groove with two axially opposite flanks and in such annular groove at least one annular seal is received for cooperation with the inner face of the housing tube fitted over it.
A known fluid power linear drive of this type is disclosed in the introductory part of the German patent publication DE 3807889 A1. Here it is a question of a power cylinder whose drive housing comprises a housing tube closed by two housing covers, the housing covers respectively having a centering portion fitting into the housing tube. For producing a seal between the housing cover and the housing tube an annular groove is machined in the outer periphery of the centering portion, to accommodate a sealing ring for cooperation with the inner face of the housing tube.
Since the production of the annular groove by machining is extremely complex the said German patent publication DE 3807889 A1 also proposed instead of having the sealing ring in an annular groove in the outer periphery of the centering portion placing it in an axial annular recess in an axially orientated terminal face of the housing cover. Such a recess may be produced as part of shaping by casting the housing cover without the need for later mechanical working without cutting. However this system is only suitable for drive housings whose housing tube has a relatively thick wall and in the case of which the housing tube is braced firmly against the housing cover axially. In conjunction with a thin-walled housing tube and even more so when the tube is to be joined radially with the inserted centering portion by a crimped joint, this type of seal is not suitable.